Margaret Hilda Thatcher, Baroness Thatcher (née Roberts (13 October 1925 – 8 April 2013), was a British politician, the longest-serving (1979–1990) Prime Minister of the United Kingdom of the 20th century, and the only woman to have held the post. A Soviet journalist called her the "Iron Lady", a nickname which became associated with her uncompromising politics and leadership style. As Prime Minister, she implemented Conservative policies that have come to be known as Thatcherism.